1. Field of the Invention
The present invention relates to cooling devices for machines, especially, but not limited to, cooling devices for the central processing unit of a desktop computer.
2. Description of the Prior Art
Heat produced as a byproduct of useful work limits the rate at which machinery can operate without melting or burning. In particular, heat limits the rate at which electronic devices, such as the central processing units of computers, can operate. The present invention uses the phase change of fluids from liquid to gas and visa versa (especially, but not limited to, water) to create a device that, without the use of movable parts, carries heat away from the machinery, to increase the rate at which it can operate.
U.S. Pat. No. 3,609,991, issued to Richard C. Chu and Un-Pah Hwang, on Oct. 5, 1971, discloses a cooling system for electronic components having thermally induced circulation. A low boiling point liquid contained in hoses (or other conduits) absorbs heat from the electronic components, causing vapor bubbles to form in the liquid by nucleate boiling. The heated, partially vaporized fluid passes into a reservoir with a cooling means, where it is cooled and condensed, and then recirculates from the reservoir back through other hoses to absorb more heat from the electronic components. The instant invention is distinguishable, in that it discloses the use of water (or other fluid) in a partial vacuum to lower its boiling point, which is contained entirely within copper pipes (or other conduits) in a closed loop, and does not require the use of special cooling means.
U.S. Pat. No. 4,393,663, issued on Jul. 19, 1983, to Howard E. Grunes and Dennis J. Morrison, discloses an apparatus for transferring heat from a heat source to a heat sink, using a vaporizable liquid which is heated in an evaporator, so that some of the liquid vaporizes to propel the remaining heated liquid to a condenser, where it is cooled and returned to the evaporator, with a "restriction" or check valve in the return path to the evaporator, to insure that the liquid flows only one way. The instant invention is distinguishable, in that only vapor leaves its evaporation chamber, and its conduit is so disposed that a check valve is unnecessary to insure flow in only one direction.
U.S. Pat. No. 4,546,619, issued on Oct. 15, 1985, to Thomas G. Rohner, discloses a mechanical cooler for electronics, containing a fluid that is made to circulate by a compressor. The instant invention is distinguishable, in that it does not require a compressor.
U.S. Pat. No. 5,168,919, issued on Dec. 8, 1992, to Jack Berenholtz and John K. Bowman, discloses an air cooled heat exchanger for multi-chip assemblies, having a self-contained evaporator and condenser, requiring no external power source. The instant invention is distinguishable, in that it has a single evaporation chamber in direct contact with the heat source, connected at its top to a single conduit into which vapor enters, condenses, and returns via a connection at the bottom of the evaporation chamber, so that the separation of liquid and gas phases in the chamber due to gravity causes the fluid to flow in one direction only through the conduit, with the conduit and the chamber forming a single closed loop.
U.S. Pat. No. 5,365,749, issued to Warren W. Porter, on Nov. 22, 1994, discloses a computer component cooling system, with local evaporation of pressurized refrigerant within an expansion chamber as it absorbs heat from the component. The instant invention is distinguishable, in that it does not require the use of an expansion chamber with movable parts to cool the circulating fluid, nor the use of a compressor to pressurize the fluid.
U.S. Pat. No. 5,383,340, issued to Ralph I. Larson, Richard L. Phillips and Alan F. Beane, on Jan. 24, 1995, discloses a two-phase cooling system for laptop computers. A fluid contained in a closed loop circulates between an evaporator located in the base of the laptop, where the fluid changes from liquid to gas as it absorbs heat from the computer, and a condenser located in the lid of the laptop, where the fluid changes from gas to liquid as it loses heat. The instant invention is distinguishable, in that it is designed for desktop computers, rather than laptop computers, and no part of it is required to be located in a lid. Also, in its preferred embodiment, the instant invention discloses the use of water as the circulating fluid, and the use of copper pipe of uniform diameter in a condensation coil.
U.S. Pat. No. 5,394,936, issued on Mar. 7, 1995, to Gerald A. Budelman, discloses a heat removal system for electric devices, in which a fluid vaporizes in a primary heat sink which is bonded directly to a heat producing electric device, then flows through a flexible tubing to a secondary heat sink, where the tubing is cooled by airflow and the fluid condenses and passes through a first check valve into a flexible bladder, then through a second check valve back through the flexible tubing to the primary heat sink. The instant invention is distinguishable, in that it has no flexible bladder or check valves, but insures that fluid flows in one direction through the orientation of its evaporation chamber and the manner in which it is connected to the conduit through which the fluid flows.
U.S. Pat. No. 5,396,775, issued to Uwe Rockenfeller and Lance D. Kirol, on Mar. 14, 1995, discloses a cooling apparatus for electronic and computer components, without the use of compressors or pumps. Heat is absorbed from the components by a complex compound of metal salts and polar refrigerants, which circulates between two reactors in which it alternately undergoes endothermic and exothermic reactions. The instant invention is distinguishable, in that it does not require the use of reactors containing metal salts and polar refrigerants.
U.S. Pat. No. 5,411,077, issued on May 2, 1995, to Lew A. Tousignant, discloses a flexible thermal transfer apparatus for cooling electronic components, with a fluid container that expands as the fluid absorbs heat and changes from liquid to gas. The vapor condenses at a location remote from the heat source, and trickles back down into the container by the same route that it left the container. The instant invention is distinguishable, in that it has a rigid, non-expandable evaporation chamber, and the fluid flows in one direction only through a closed loop.
U.S. Pat. No. 5,427,174, issued on Jun. 27, 1995, to Paul A. Lomolino, Sr. et al., discloses a method and apparatus for a self contained heat exchanger for cooling a solid state electronic device, using a mixture of two or more coolants within one or more hermetically sealed chambers, within which the coolant circulates. The coolants should have different boiling points, so that the lower boiling point fluid agitates that higher boiling point fluid, causing it to circulate within the chamber, so that heat is transferred. The instant invention is distinguishable, in that it does not require more than one fluid as a coolant, and the coolant circulates through a tubular conduit that is separate from its evaporation chamber.
U.S. Pat. No. 5,430,609, issued to Dan Kikinis, on Jul. 4, 1995, discloses a method of cooling a microprocessor in a portable computer, using a layer of compressible, heat-conducting material. The instant invention is distinguishable, in that it uses a circulating fluid, rather than a heat sink plate.
U.S. Pat. No. 5,529,115, issued on Jun. 25, 1996, to Robert W. Paterson, discloses a cooling device for an integrated circuit device, including a chamber that is partially filled with a coolant which forms a pool in the chamber. Heat generated by the integrated circuit device causes boiling of the coolant in the pool, so that vaporized coolant rises and condenses on a ceiling of the chamber, and then drops back down into the pool. Vapor and drops of condensed coolant travel through conduits in the chamber, but do not leave the chamber, and vapor and condensed coolant travel in opposite directions through the same conduits. The instant invention is distinguishable, in that in it the fluid flows in only one direction through a conduit that is external to the evaporation chamber.
U.S. Pat. No. 5,587,880, issued to Richard J. Phillips and Ralph I. Larson, on Dec. 24, 1996, discloses a computer cooling system operable under the force of gravity in a first orientation, and against the force of gravity in a second orientation. Fluid circulates between an evaporator in which heat is absorbed, and a condenser in which heat is dissipated. A check valve ensures that: the fluid flows in only one direction. The instant invention is distinguishable, in that it does not include a check valve, and operates in only one orientation. Also, in its preferred embodiment, the instant invention discloses the use of water as the circulating fluid, and the use of copper pipe of uniform diameter in a condensation coil.
U.S. Pat. No. 5,634,351, issued to Ralph I. Larson, Richard J. Philips and Alan F. Beane, on Jun. 3, 1997, discloses a two-phase cooling system for a laptop computer, which differs from the above-mentioned U.S. Pat. No. 5,383,340 in that the evaporator and the condenser are both included in either the lid or the base of the computer. The instant invention is distinguishable, in that it is designed for desktop computers, rather than for laptop computers, and is not required to have a lid housing a screen and a base housing a keyboard. As mentioned before, in its preferred embodiment, the instant invention discloses the use of water as the circulating fluid, and the use of copper pipe of uniform diameter in a condensation coil.
U.S. Pat. No. 5,704,416, issued on Jan. 6, 1998, to Ralph I. Larson and Richard L. Phillips, discloses a two-phase component cooler, having a container that has at least one wall with sufficient flexibility that the wall expands as the coolant vapor expands. The instant invention is distinguishable, in that in it the evaporation chamber and the conduit do not expand as liquid in them is vaporized.
U.S. Pat. No. 5,761,037, issued on Jun. 2, 1998, to Timothy Merrill Anderson et al., discloses an orientation independent evaporator, including a wicking member possessing a number of surface accessible channels. Because of the wicking member, the evaporator is able to be operated in any orientation with respect to a gravitational field. The instant invention is distinguishable, in that in it does not have a wicking member, and can only operate within a range of orientations with respect to a gravitational field, as it makes use of gravity to cause the fluid to move in one direction only.
British Patent No. 2,199,650, issued to the Sundstrand Corporation, application published on Jul. 13, 1988, discloses a means for cooling electronic components, with a fluid that circulates without the use of moving parts through capillary channels, between an evaporator in which it absorbs heat and changes from liquid to gas, and a condenser in which it dissipates heat and changes from gas to liquid. The invention is distinguishable, in that it uses copper pipes or similar conduits, rather than capillary channels.
British Patent No. 2,204,113, issued to Marconi Electronic Devices Limited, application published on Nov. 2, 1988, discloses a phase change cooling arrangement for components such as semiconductors, with a chamber containing liquid which is partially vaporized when it absorbs heat, and means for monitoring the temperature difference between the evaporating chamber and the condenser. The instant invention is distinguishable, in that in it the fluid circulates in a single closed loop.
German Patent No. 3,244,654, issued to Gbsta Lundqvist, on Jul. 9, 1983, discloses a cooling unit for electronic equipment, in which heat is absorbed from operating components by heat exchangers and carried off by a refrigerating fluid that passes through multiple tubes. The invention is distinguishable, in that it uses water or other fluid that undergoes phase changes while circulating within a single closed tubular loop.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.